I-membrane ye-plasma: imingcele efihliwe

Ukuphila kweseli kuyaba khona kuphela ngoba ama-enzyme ahlukene nezinto azihlanganisi, futhi iseli lenza konke. Konke lokhu kungenzeka kuphela ngokusebenzisa izibungu ezihlukahlukene. Futhi iseli lonke lihlukaniswa kwabanye ngesakhiwo esikhethekile esibizwa ngokuthi "i-cytoplasmic membrane".

Ingabe ibonakala ku-microscope elula? Impendulo ayibi, yebo, sibona imingcele, kodwa i-membrane ngokwayo isakhiwo esincane kakhulu. Ngezinye izikhathi asiboni ngisho nomngcele wamaseli, isibonelo, uma sihlola amangqamuzana wesibindi ku-microscope elula. Kodwa kungani-ke, kwezinye izimo, sibona imingcele yamaseli, akusiyo yini isibhande?

Eqinisweni, lawa angama-carbohydrates angenhla angenhla, aphakathi kwamaseli. Bamba idayi, ngakho-ke ngokunquma okuphumelelayo ungase ucabange ukuthi lokhu kuyi-membrane ye-plasma.

Ekuvivinyweni, kwatholakala ukuthi amangqamuzana afakwa ezixazululweni ezihlukahlukene ezicindezelayo ze-osmotic zivuvukala noma zinkimbinkimbi, okusho ukuthi zizungezwe i-membrane ekhonjiswe ngokubonakalayo okukhethiwe.

Kwafunyanwa futhi ukuthi i- membrane yeseli iphethwe kahle uma izinto ezincibilika ku lipids zama ukungena. Esikhathini somqondo we-classical, i-hydrophilic ekupheleni kwe-molecule ye-membrane kwakubhekwa sengathi ivulelwe ngaphandle, futhi i-hydrophobic iphetha ngaphakathi. I-electron microscopy iye yafakazela ukuthi le ndaba yinkimbinkimbi kakhulu. Ngokuyinhloko, ezithombeni ze-elekthronikhi, kungabonakala ukuthi izingxenye zangaphandle ziba mnandi, hhayi ngaphakathi, okungukuthi, izingqimba ze-lipid zikhona emaphethelweni.

I-membrane ye-plasma ayikwazi ukungenakwenzeka kuma-macromolecules ngenxa yesakhiwo sayo, ngakho-ke amaprotheni ayi-cytoplasm akakwazi ukuphuma esitokisini ngawo. Amaprotheni, abe esesitokisini, yakha ingcindezi ye-osmotic, ngenxa yokuthi inani elidingekile lamanzi lingena ngaphakathi kweseli. Kodwa-ke, le nqubo ayinakuphela, ngoba emzimbeni wezicubu ezivela ngaphandle futhi kukhona nezinye izinto ezivimbela ukucindezela kwe-osmotic.

Ukuze umehluko ongase ube khona ukuhlala uzinzile, i-membrane ye-plasma kufanele ibe nezindawo ze-dielectric. Lokhu futhi kwaholela ososayensi emcabangweni wokuthi kunezinhlobo eziningi ze-lipids embranini enezakhi ze-dielectric. Ngokwehluleka kwembula izindawo zayo zekhanda le-plasma.

Isakhiwo nemisebenzi yaso ixhunyiwe, isibonelo, ikhono lokugcina umehluko ongajwayelekile emigomeni ye potassium kanye ne-sodium ions kuhlotshaniswa nenqubo ekhethekile embranini - ipompodi ye-sodium-potassium. Ukudluliswa kwe-ions kulokhu kwenziwa nge-enzyme ekhethekile, esebenza ngamandla esitokisini, le nqubo iyabiza kakhulu. I-cage kufanele "ikhokhele" ibhalansi. Futhi zidinga "utshalomali" kanye nokudluliswa kwe-glucose, ama-fatty acids, ama-amino acids.

Isakhiwo esithakazelisayo se-membrane yeseli naso-asymmetry yayo, okungukuthi, ukungena kwayo kwangaphakathi nangaphandle akufani, nakuba ekuqaleni abacwaningi basekelwe ku-data ye-electron microscopy bakholelwa lokhu. Zonke izingxenye ze-glycoprotein eziqukethe i-hydrocarbon zihamba ngaphesheya kwendawo yangaphandle yekhanda futhi zibambe iqhaza ekwakheni uhlaka lwe-supercilipid. Ingaphandle yangaphandle yeseli ibuye iqukethe ama-molecule akhethekile okuthiwa ama-receptors, enza nge-molecule ethile yemvelo yangaphandle. Ngakho umsebenzi weseli ulawulwa, ungavuselelwa noma uphonswe ngokuya ngezidingo zomzimba. Futhi engxenyeni yangaphakathi ye-ambulance inezinhlobo eziningi ze-cholesterol.

Ucwaningo lwezinto ezinokwemvelo lwe-membrane yeseli luye lwabonisa ukuthi amaprotheni wezingqimba zangaphakathi nezingaphandle azifani, futhi amaphospholipid ahlukahlukene kulezi zindawo ezimbili nawo ahlukene kakhulu. Ezinye zalezi zici zingabonakala ngisho ne-microscope ye-electron.

Njengoba ubona, isibhande sokuqala asiyona elula, futhi ukuze siqonde zonke izinqubo ezenzekayo, ososayensi kwakudingeka bakhe futhi banqabe imibono eminingi.